Social Skills are Disappearing

I do some work with a conservation group and we are often at events where we interact with the public. At least we _try_ to interact with the public. Often a simple "hello" or "good morning" gets no response or some inarticulate grunting in return. Some people have not been told it is rude to stand and stare (especially with their mouths open) or ignore people. They'll turn their backs on you and walk away as if you don't exist. If they do talk to you they ask the most bizarre things "Is that real wood?" or go "ugh" when you say you eat the berries that grow wild in the woods. These are not youngsters but adults who often have kids in tow (I dread to think how those kids are going to turn out). Why is it that I suspect that the only way you can get them to talk to you is via a mobile 'phone or the internet? Why don't people have any basic social skills or manners any more?